A bug in the algorithm for triangulating a graph by (Tarjan 1984)

About one year ago, my student Qiyuan Hu noticed a strange thing when trying to triangulate the graph of a Qualitative Constraint Network (QCN). In particular, when we apply the triangulation algor...

Java Jar Building

Why it always says could not find or load main class

Extracting to jar file makes it convenient to run a Java program from command line. But today I encountered a problem of extracting jar file with IntelliJ Idea. The problem is that after using the...

R ggplot2 confusions

Greek letter mu is not correctly displayed

R is powerful and ggplot2 makes it more accessible. Recently, I need to create a plot that has the Greek letter \(\mu\) displayed as a label. First I tried the following script in terminal r <- ...